Abhishek Srivastava asked: Should I use "Could you please..." or "Would you please..."?
Both of these choices are polite ways to ask someone to do something, as in:
Could you please email me the directions to your house?
Would you please email me the directions to your house?
For most speakers, these are two ways of asking the exact same thing.
Of course, if either of these questions is asked with an angry voice and intonation, the meaning changes. Imagine a frustrated mother or father looking at a teenager and saying:
Could you PLEASE turn off the lights in your room?
This is not a polite request, but an angry request, and a complaint about something that the teenager hasn't done. And if the teenager wants to complain back, he or she can say:
I said I will when I go upstairs. Would you PLEASE stop asking me that?